Container closure

ABSTRACT

A flexible closure is provided with a flexing groove in the closure top and a sealing groove in a downwardly depending skirt adapted to conform substantially to the opposing surface of a beaded container rim to form a seal with the beaded rim although the closure is considerably flexed by a container of greater than optimum diameter.

United States Patent Kinney 1 Feb. 15, 1972 [54] CONTAINER CLOSURE3,269,588 8/1966 Ruekberg ..220/60 R [72] Inventor: Alfred W. Kinney,Kansas City, MO. FOREIGN PATENTS OR APPLICATIONS [731 Assignw PhillipsPelmkum Company 686,402 5/1964 Canada ..220/60 R 22 i July 20, 1970865,039 4/ 1961 Great Britain ..215/41 [2]] Appl' 56,374 PrimaryExaminer-George E. Lowrance Attorney-Young and Quigg [52] [1.8. CI...220/60 R, 215/41 [51] Int. Cl. ....B65d 43/10, 865d 41/22 ABSTRACT[58] Field of Search ..220/60 R; 215/41; 229/43 A flexible closure isprovided with a flexing groove in the sure top and a sealing groove in adownwardly depending skirt [56] References Cited adapted to conformsubstantially to the opposing surface of a UNITED STATES PATENTS beadedcontainer rim to form a seal with the beaded rim although the closure isconsiderably flexed by a container of l I 1 5 Blakeslee ..2 l greaterthan optimum diameten 2,586,775 2/1952 Benner ..215/41 X Cserny ..220/60R x 5 Claims, 6 Drawing Figures PATENTEUFEB15 I972 3.64216? INVENTOR.

A. W. KINNEY A T TORNE VS CONTAINER CLOSURE This invention relates to aformed closure for a container. In one aspect, it relates to a closuremade of flexible material. In another aspect, it relates to a reusableclosure for a container. In still another aspect, it relates to aclosure for a container having a beaded rim. In yet another aspect, itrelates to a closure that forms a moisture retentive seal with acontainer. In yet another aspect, it more specifically relates to aclosure suited for retaining the moisture content within a dairy productcontainer.

A great number of container closures have been formed of flexible sheetmaterial, such as synthetic therrnoplastics. Some of these closures havebeen of a stopper type, fitting inside the bore of a container opening.Others have been of the covering type, which fit over the outside of thecontainer opening and seal around a head or other sealing deviceprovided on the exterior of the container opening. This invention isconcerned with the latter type of closure.

The design of conventional snap-on coverall closures, particularly thestandard injection molded polymer closures, is such that only linecontact is achieved when the closure contacts the container brimdiameter. A line contact seal is unsatisfactory in many applicationsbecause it does not provide a good hermetic seal so that products with ahigh moisture content lose 1 percent or more of their moisture in a7-day period when packed in such a container. Unfortunately thelimitations of production equipment and production materialcharacteristics make it impractical to hold dimensional tolerances onthe brims of thermoformed plastic containers within limits that assuresatisfactory sealing of conventional snap-on coverall closures. Evenwithin practical tolerance limits as the diameter of the brim of thecontainer increases to its upper tolerance limit the closure skirtangles outward moving the line of contact between the closure and thecontainer brim toward the top of the rolled brim or beaded rim of thecontainer thus reducing the effectiveness of the seal.

It is therefore an object of this invention to provide a container witha closure with improved moisture retentive sealing qualities. It is afurther object of this invention to provide an economical, tight sealingclosure for high moisture content product containers such as dairyproduct containers. It is a further object of this invention to providea flexible closure that is reusable. It is a further object of thisinvention to provide a closure that is stackable. It is a still furtherobject of this invention to provide a closure that allows a widertolerance of size differential in container closures and container brimdiameter without reducing sealing qualities.

These and other objects are achieved by the container closure of ourinvention as described in this specification, the drawings and theappended claims.

According to the invention a container closure is made of flexiblematerial and is adapted to have the sealing groove on the inside of thedownwardly depending skirt conform substantially to the opposed surfacesof the beaded rim of the container to which it is fitted so that onflexing the container closure, the sealing groove and flexing groove actin conjunction to continue conformation of the container closure grooveto the opposed surface of the beaded rim of the container to which theclosure is fitted.

The closure of the invention can be readily seen by reference to thedrawings,

FIG. I shows two closures of the invention in stacked relationship.

FIG. 2 shows the sealing groove of the invention applied to the beadedrim that it was contoured to fit.

FIG. 3 shows an alternativecontour for the closure.

FIG. 4 shows a conventional coverall closure in perfect alignment with abeaded rim.

FIG. 5 shows a conventional coverall closure as aligned with a beadedrim of a container the diameter of which is approaching the maximumtolerable.

FIG. 6 shows a closure of this invention in alignment with a beaded rimof a container the diameter of which is ap proaching the maximumtolerable.

Referring now to FIG. 1, the closure of our invention which is aone-piece closure, preferably made by thermoforming can be seen. Thedistinctive feature of the closure of this invention is the conformationof the sealing groove inside the downwardly depending skirt to thecontour of the beaded rim of the container to which the closure is to beattached. The closure is formed having a central discoidal portion 11.At its perimeter, this discoidal portion is provided with an upstandingwall structure in the shape of a conical frustum of increasing diameterfrom bottom to top 12 which terminates at its top in an outwardlyextending annular ring portion increasing in thickness towards the outerperimeter 14 and forming in conjunction with the conical frustum portionan outwardly extending groove on the inside of the closure 15 whichserves as a flex point in the closure top. In the outer extremity of theannular ring 13 in the area of increased thickness 14 is a downwardlydepending skirt 16. The skirt is of generally decreasing thickness fromtop to bottom and contains in its inside wall a sealing groove 17 whichis conformed to the contour of the beaded rim of the container it willbe used to close.

In the embodiment shown in FIG. 1, the skirt portion is offset from theouter periphery of annular ring portion and depressed from the upperedge of the annular ring portion to produce a groove on the upper outerperimeter of the closure which aids in the stacking of the closures. Theclosures are stacked by fitting the lower extremity of the skirt portionof one closure into the stacking groove of another closure.

FIG. 2 shows a closure of my invention applied to a container opening.The complete conformation of the closure seal groove 17 to the contourof the surface of the beaded rim of the container 19 is shown in thisembodiment. In another embodiment shown in FIG. 3, the sealing groove 17is shaped so that only the lower half of the sealing groove forms thecontour of the are described by the radius of the curvature of thebeaded rim of the container 19. The upper portion of the sealing groovemay be squared off as illustrated 20, or can be a rounded fillet orother shape. The most important aspect of the invention is that thelower half of a sealing groove be able to conform to the curvature ofthe beadedrim if the area of sealing contact is forced to move towardthe top of the beaded rim of the container because the containerdiameter is approaching the maximum that the closure can toleratewithout the downward depending skirt being flexed to such a degree thatthe closure cannot be retained on the bead rim. Thus, it can be seenthat by conforming the shape of the sealing groove to the contour of thecontainer beaded rim an area of contact can be maintained to maintain amoisture retentive seal between the closure and the container eventhough the closure is considerably stretched and flexed by a containerdiameter of greater than optimum size.

Referring now to FIG. 4, a conventional snap-on, coverall closure isshown applied to a container with optimum size opening. It will be seenthat the contact between the closure 21 and the container beaded rim 19,is, at most, little more than line contact 22. When a conventionalclosure is applied to a container opening of greater than optimum sizethe line of contact 22 between the closure 21 and the beaded rim of thecontainer 19 rides up toward the top of the container brim and canestablish another line contact 23 between the closure top portion andthe top of the container rim, as shown in FIG. 5. These line contactsare insufficient, however, to prevent the loss of moisture content fromwithin the closed container as is accomplished by the seal produced bythe closure of this invention shown in FIG. 6. v

The closure of my invention is generally made of a syntheticthermoplastic material. Polyolefins, polystyrene and polyvinyl chlorideare particularly preferred for such an application, although theinvention is not limited to these materials but may include otherthermoplastic materials alone or in a laminated form such as athermoplastic coated paper.

The closures of this invention can be used with any container having arounded beaded rim. As stated above, the invention is particularlyapplicable to closures for containers for EXAMPLE 1 To containers wereadded 100 grams of water. These containers were fitted with lids of theprior art design and weighed after closure. Ten more containers weresimilarly treated, but were fitted with closures of the design of thisinvention. After 6 days of shelf storage all the closed containers wereweighed again.

Weight Loss,

Type Closure Range Average Prior Ar! 0.63 to 1.24 1.01 This lnvention0.6l to 095 0.73

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure and the drawings, the essence of which is thatthere has been provided a closure of flexible material containing asealing groove in the skin conformed to the contour of the beaded rim ofthe container to which it is applied to provide a reliable moistureretentive seal with the closed container.

We claim:

1. A flexible closure adapted to be fitted on a container having abeaded rim comprising:

a. a central discoidal portion,

b. a conical frustum portion of increasing diameter extending upward andradially outward from the periphery of said discoidal portion,

c. a radially outward extending annular portion attached to the top ofsaid conical frustum portion and of increased thickness toward theradially outer periphery, forming in conjunction with said conicalfrustum portion an upwardly extending groove on the inside of theclosure, and

d. a downwardly depending skirt of decreasing thickness attached to saidthickened annular portion, said skirt containing on its inside a groovewhich conforms substantially to the opposed surface of the beadedcontainer rim to which it is to be fitted.

2. The closure of claim 1 wherein said downwardly depending skirtcontains on its inside a groove the lower half of which conformssubstantially to the opposed surface of the beaded container rim towhich it is to be fitted.

3. The closure of claim 1 wherein said downwardly depending skirt isoffset from said annular portion to produce a groove on the outerperimeter of the top of the closure.

4. The closure of claim 1 wherein said flexible material is a syntheticorganic thermoplastic.

5. The closure of claim 1 in combination with a container provided witha beaded rim at its opening wherein the beaded rim of the container andthe groove contained in the skirt of the closure are adapted to form amoisturetight seal.

1. A flexible closure adapted to be fitted on a container having abeaded rim comprising: a. a central discoidal portion, b. a conicalfrustum portion of increasing diameter extending upward and radiallyoutward from the periphery of said discoidal portion, c. a radiallyoutward extending annular portion attached to the top of said conicalfrustum portion and of increased thickness toward the radially outerperiphery, forming in conjunction with said conical frustum portion anupwardly extending groove on the inside of the closure, and d. adownwardly depending skirt of decreasing thickness attached to saidthickened annular portion, said skirt containing on its inside a groovewhich conforms substantially to the opposed surface of the beadedcontainer rim to which it is to be fitted.
 2. The closure of claim 1wherein said downwardly depending skirt contains on its inside a groovethe lower half of which conforms substantially to the opposed surface ofthe beaded container rim to which it is to be fitted.
 3. The closure ofclaim 1 wherein said downwardly depending skirt is offset from saidannular portion to produce a groove on the outer perimeter of the top ofthe closure.
 4. The closure of claim 1 wherein said flexible material isa synthetic organic thermoplastic.
 5. The closure of claim 1 incombination with a container provided with a beaded rim at its openingwherein the beaded rim of the container and the groove contained in theskirt of the closure are adapted to form a moisturetight seal.